In 2252, Yu was assigned a mission to planet Delta Aurigae III. Ensign Spock was assigned to take over the bridge science station during Yu's temporary absence. (TOS - Constellations short story: "Chaotic Response")
- In "Chaotic Response", Yu is mentioned only in a hallucinatory memory of Spock's, and thus may have only been an invention of his imagination.
By 2257 Yu was serving aboard the USS Farragut as the ship's helmsman. In that year, Yu was at his station on the bridge when the Farragut came under attack by a dikironium cloud creature whilst in orbit of Tycho IV. Yu was killed along with all other personnel on the bridge, except Ensign Konerko. (TOS - My Brother's Keeper novel: Constitution)
- The Yu who appeared in Constitution may be a different person to the one mentioned in "Chaotic Response", but with no confirmation either way, they are assumed to be the same person.
|USS Farragut personnel|
|USS Farragut (NCC-1647)||Akanke • Ayers • K. Bogle • A. Chenowyth • Crane • A. Drake • Galt • Garrovick • Gilhooley • Hasegawa • T. Kegin • Hellund • Kelly • Keyes • J.T. Kirk • Konerko • V. Leigh • McKone • G. Mitchell • F. Morgan • D. Morwood • Ojibwe • Pavano • Piniella • Poquette • N. Rabin • Smiley • L.H. Styles • Tolan • Vosberg • Yu • unnamed personnel|
|USS Farragut (NCC-1729)||Bogle • P. Ellis • J. Gustavus • Phillips • R. Lee • D. Rodrieguez|
after being renamed USS Centurion: G. Aldus • J. Apius • C. Caecus • M. Secondus • L. Sejanus • J. Sicania • M. Volcinius
|USS Farragut (NCC-2582)||W. Ross|
|J.T. Kirk • S. Garrovick • N. Uhura|